Boys and girls,
last night I was just about to button up a Omni V I have been working on. Doing
a calibrate on the internal power out meter and verify the SWR was reading
correctly..
I placed the Omni V in 'tune' and with the output into my cantenna, I started
to do check the calibration.
Then I was distracted. Don't know by what or for what reason, but i found
myself sitting in front of the TV watching a movie. After the movie was over,
my wife said she smelled what she said was the oder of paint.
Running into the room, the smell of hot paint rushed into my nose.
I looked down and the Omni V was in transmit, 100 watts showing on the bird
thruline. The dummy load was almost on fire, oil bubbled out of the pressure
valve. The heatsink on the back of the radio was so hot the entire rear of the
radio was too hot to touch! The paint smell was from the top and rear apron of
the rig.
I grabbed a muffin fan and quickly had it blowing air across the rear of the
rig.
It took almost an hour to cool the rig down to the point I could touch it.
Thinking I just screwed up big time, I wondered if any of the parts inside the
PA had un-soldered, I dug out another dummy load, held my breath, and pushed
the 'tune' button.
Up she came, 100 watts on all bands.
Damn...
The Omni V was keyed for over two and half hours and while hotter than hell,
suffered no ill effects. That's a statement of a well designed solid state
amplifier.
And on a side note, the MFJ "cube" switching power supply I use on my service
bench held up as well. It's too was at the melting point,
I remember when W8AU left his Triton 4 in keydown inside his car for an hour,
it too survived.
Could have been worst. A lesson learned. Battery replaced in smoke detector in
shack.
mike wb8vge
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